Materials Literature
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The kinetics of anisotropic β‐Si 3 N 4 grain growth in silicon nitride ceramics were studied. Specimens were sintered at temperatures ranging from 1600° to 1900°C under 10 atm of nitrogen pressure for various lengths of time. The results demonstrate that the grain growth behavior of β‐Si 3 N 4 grains follows the empir…
The oxidation of iodide by 1 MHz continuous ultrasound and the sonoluminescence in water created by pulsed ultrasound were investigated in the pressure range from 0.7 to 3 bar. At low intensities, the chemical yield and the luminescence intensity decrease with increasing pressure. At higher intensities the yields incr…
Using cross-linking stereochemistry as indicators, the molecular environment of two collagens in the turkey leg Achilles tendon were compared. The tendon from one year old turkeys was dissected into nonmineralized, fully mineralized and transitionally mineralized portions. Amino acid composition and cyanogen bromide p…
The kinetics of electrochemical aniline polymerization in aqueous acidic solutions have been investigated by chronocoulometry as a function of the electrolyte anion (i.e. HSO4–, Cl–, NO3–, ClO4–, CF3CO2–), concentration of aniline and para-phenylenediamine (PPDA) as an additive and also in terms of potential or curren…
The chemisorbed species on diamond surfaces have been studied by Fourier-transform infrared (FTIR), temperature-programmed desorption (TPD) and laser Raman spectroscopy. Oxidized diamond powders were treated thermally in an H2 environment. IR spectral changes were followed during the hydrogenation of oxidized diamond…
The stabilities of various porphin analogue compounds such as unsubstituted and substituted phthalocyanines, tetraphenylporphyrin, naphthalocyanine and tetraazaporphyrin have been investigated. The compounds were dissolved either in organic solvents or water. Electronic spectra in the visible region were recorded afte…
Particle removal from silicon wafer surfaces was studied using acid and alkaline solutions employed in wet cleaning processes found in semiconductor manufacturing. It was demonstrated that alkaline solutions are superior to acid solutions in terms of particle removal efficiency. The following particle removal mechanis…
Abstract The synthesis of high‐molecular‐weight polyesters based on 1,4:3,6‐dianhydro‐ D ‐sorbitol (DAS), 1,4:3,6‐dianhydro‐ D ‐mannitol (DAM) and 1,4:3,6‐dianhydro‐ L ‐iditol (DAI) is reported. The polymers were obtained by polycondensation in solution of the dianhydrohexitols with terephthaloyl dichloride and 2,5‐di…
Molecular dynamics simulations are used to test macroscopic theories for static and dynamic contact angles. Young's equation is verified by comparing observed static contact angles to angles calculated from the independently measured surface tensions between phases. Laplace's relation between the interfacial curvature…
Replacement of nickel by aluminium in the brucite-type Ni(OH)2 layers leads to layered double hydroxides (LDH), which can be used as active materials for nickel hydroxide electrodes. Ni/Al LDH compounds [0 < Al/(Ni + Al)⩽ 0.25] were synthesized by precipitation with ammonia from mixed Ni/Al nitrate solutions and chara…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRelation of effective interaction parameters for binary blends and diblock copolymers: lattice cluster theory predictions and comparisons with experimentJacek Dudowicz and Karl F. FreedCite this: Macromolecules 1993, 26, 1, 213–220Publication Date (Print):January 1, 1993Publ…
Abstract
The effects of halogenation and aggregation on photosensitizing properties of zinc phthalocyanine (ZnPC) have been examined by photophysical methods. Halogenation decreases the fluorescence yield and lifetime, increases triplet formation and shortens the triplet lifetime. These effects, which increase in the order Cl…
A Weibull statistical analysis of breakdown voltages of thin polyethylene-insulated power cable slices is performed on large populations. Computation of confidence intervals implies that the statistically correct description is a three-parameter Weibull distribution, i.e., with a nonzero location parameter. It is show…
The purpose of this review is to compare the tableting properties of conventional microcrystalline cellulose (MCC) with those of other common direct compression diluents and of the numerous new MCC grades and brands recently made available. After a brief discussion of the mechanisms of consolidation involved in the fo…
A bimolecular Diels–Alder reaction is accelerated substantially and stereoselectively by binding diene and dienophile within the cavity of a cyclic metalloporphyrin trimer.
Refractive indices of two nematic liquid crystals, 5CB and 5PCH, were measured from the 400- to 800-nm region at various temperatures. Results fit the three-band model well. Through comparisons, the contributions of σ and π electrons to the refractive indices and birefringence of uniaxial liquid crystals are evaluated…
The behavior of 138 kV nonceramic line post insulators is investigated by means of clean fog tests conducted before and after aging in a specially designed accelerated aging chamber. The laboratory aging cycles are justified on the basis of actual weather in the coastal regions of Florida. Analytical measurements quan…
Addition of α‐Fe 2 O 3 seed particles to alkoxide‐derived boehmite sols resulted in a 10‐fold increase in isothermal rate constants for the transformation of γ‐ to α‐Al 2 O 3 . Changes in porosity and surface area with sintering temperature showed no effect of seeding on coarsening of the transition alumina gels, but…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNanoscale metal oxide particles as chemical reagents. Intrinsic effects of particle size on hydroxyl content and on reactivity and acid/base properties of ultrafine magnesium oxideHidenobu Itoh, Suchada Utamapanya, Jane V. Stark, Kenneth J. Klabunde, and John R. SchlupCite t…